Polymarket Copy Trading Bot

Skill by ara.so — Daily 2026 Skills collection.

A TypeScript bot that continuously monitors a target Polymarket wallet, detects trades in real time via REST polling and/or WebSocket, and mirrors BUY orders to your own account using the Polymarket CLOB SDK on Polygon mainnet.

What It Does

Monitors a target wallet via Polymarket Data API (REST polling every ~2s) and optionally WebSocket
Mirrors BUY trades only — SELL trades are detected but skipped by default
Sizes copies using a configurable POSITION_MULTIPLIER (default 10%) with min/max caps
Submits orders as FOK, FAK, or LIMIT via the Polymarket CLOB client
Enforces risk limits — per-session and per-market notional caps
Supports three auth modes — EOA (SIG_TYPE=0), Poly Proxy (SIG_TYPE=1), Poly Polymorphic (SIG_TYPE=2)

Installation

git clone https://github.com/Neron888/Polymarket-copy-trading-bot.git
cd Polymarket-copy-trading-bot
npm install

Requires Node.js v18+. The CLOB SDK requires ethers v5 (already pinned in package.json).

Configuration

cp .env.example .env

Edit .env:

# Required
TARGET_WALLET=0xTargetWalletAddressToMonitor
WALLET_PRIVATE_KEY=0xYourPrivateKey
RPC_URL=https://your-quicknode-polygon-endpoint.quiknode.pro/your-key/

# Auth mode (0=EOA default, 1=Poly Proxy, 2=Poly Polymorphic)
SIG_TYPE=0
# Required only for SIG_TYPE=1 or 2
PROXY_WALLET_ADDRESS=

# Sizing
POSITION_MULTIPLIER=0.1      # 10% of target's trade size
MAX_TRADE_SIZE=100            # Max USDC per copied trade
MIN_TRADE_SIZE=1              # Min USDC per copied trade

# Order behavior
ORDER_TYPE=FOK                # FOK | FAK | LIMIT
SLIPPAGE_TOLERANCE=0.02       # 2%

# Risk caps (0 = disabled)
MAX_SESSION_NOTIONAL=500      # Total USDC for entire session
MAX_PER_MARKET_NOTIONAL=100   # Per market USDC cap

# Monitoring
USE_WEBSOCKET=true
POLL_INTERVAL=2000            # ms between REST polls
USE_USER_CHANNEL=false        # true = user WS channel, false = market channel

# Optional
POLYMARKET_GEO_TOKEN=
WS_ASSET_IDS=                 # comma-separated asset IDs for market WS
WS_MARKET_IDS=                # comma-separated condition IDs for user channel
MIN_PRIORITY_FEE_GWEI=30
MIN_MAX_FEE_GWEI=60

Key Commands

# Start the bot (development mode with ts-node)
npm start

# Generate and persist API credentials to .polymarket-api-creds
npm run generate-api-creds

# Validate existing API credentials
npm run test-api-creds

# Compile TypeScript to dist/
npm run build

# Run compiled production build
npm run start:prod

Architecture Overview

index.ts
  └── TradeMonitor      — REST polls Polymarket Data API for new target trades
  └── WebSocketMonitor  — Optional low-latency WS subscription (market or user channel)
  └── TradeExecutor     — Sizes trade, checks balance/allowance, submits CLOB order
  └── PositionTracker   — In-memory positions updated on fills
  └── RiskManager       — Session + per-market notional enforcement

Execution flow:

detect trade → BUY? → subscribe WS if needed → compute copy size
  → risk check → execute order (FOK/FAK/LIMIT) → record fill → update stats

Code Examples

Starting the bot programmatically

import { startBot } from './src/index';

// The bot reads all config from process.env / .env
startBot();

TradeMonitor — polling pattern

import { TradeMonitor } from './src/TradeMonitor';

const monitor = new TradeMonitor({
  targetWallet: process.env.TARGET_WALLET!,
  pollInterval: Number(process.env.POLL_INTERVAL ?? 2000),
});

monitor.on('trade', (trade) => {
  console.log('New trade detected:', trade);
  // trade.side: 'BUY' | 'SELL'
  // trade.asset: token ID (outcome token address)
  // trade.size: USDC size
  // trade.price: fill price (0–1)
});

monitor.start();

TradeExecutor — placing a copy order

import { TradeExecutor } from './src/TradeExecutor';
import { ClobClient } from '@polymarket/clob-client';
import { ethers } from 'ethers';

const provider = new ethers.providers.JsonRpcProvider(process.env.RPC_URL);
const signer = new ethers.Wallet(process.env.WALLET_PRIVATE_KEY!, provider);

const clobClient = new ClobClient(
  'https://clob.polymarket.com',
  137, // Polygon chainId
  signer,
  apiCreds,          // loaded from .polymarket-api-creds
  Number(process.env.SIG_TYPE ?? 0),
  process.env.PROXY_WALLET_ADDRESS || undefined,
);

const executor = new TradeExecutor({
  client: clobClient,
  positionMultiplier: Number(process.env.POSITION_MULTIPLIER ?? 0.1),
  maxTradeSize: Number(process.env.MAX_TRADE_SIZE ?? 100),
  minTradeSize: Number(process.env.MIN_TRADE_SIZE ?? 1),
  orderType: (process.env.ORDER_TYPE ?? 'FOK') as 'FOK' | 'FAK' | 'LIMIT',
  slippageTolerance: Number(process.env.SLIPPAGE_TOLERANCE ?? 0.02),
});

// Copy a detected trade
await executor.copyTrade({
  side: 'BUY',
  tokenId: '0xAssetId...',
  originalSize: 12.5,   // USDC from target's trade
  price: 0.62,
});

RiskManager — checking before execution

import { RiskManager } from './src/RiskManager';

const riskManager = new RiskManager({
  maxSessionNotional: Number(process.env.MAX_SESSION_NOTIONAL ?? 0),
  maxPerMarketNotional: Number(process.env.MAX_PER_MARKET_NOTIONAL ?? 0),
});

const allowed = riskManager.checkTrade({
  marketId: '0xConditionId...',
  notional: copySize,
});

if (!allowed) {
  console.log('Trade blocked by risk limits');
}

WebSocket monitor — low-latency subscription

import { WebSocketMonitor } from './src/WebSocketMonitor';

const wsMonitor = new WebSocketMonitor({
  useUserChannel: process.env.USE_USER_CHANNEL === 'true',
  assetIds: process.env.WS_ASSET_IDS?.split(',').filter(Boolean) ?? [],
  marketIds: process.env.WS_MARKET_IDS?.split(',').filter(Boolean) ?? [],
});

wsMonitor.on('orderFilled', (fill) => {
  console.log('Fill received via WS:', fill);
});

wsMonitor.connect();

Authentication Modes

EOA (default — `SIG_TYPE=0`)

SIG_TYPE=0
WALLET_PRIVATE_KEY=0xYourKey
# PROXY_WALLET_ADDRESS — leave empty

On first run, the bot auto-submits USDC.e/CTF approval transactions. Wallet needs POL for gas.

Poly Proxy (`SIG_TYPE=1`)

SIG_TYPE=1
WALLET_PRIVATE_KEY=0xSignerKey
PROXY_WALLET_ADDRESS=0xYourPolymarketProxyAddress

Poly Polymorphic (`SIG_TYPE=2`)

SIG_TYPE=2
WALLET_PRIVATE_KEY=0xSignerKey
PROXY_WALLET_ADDRESS=0xYourPolymorphicSafeAddress

Generating API Credentials

npm run generate-api-creds

This derives API keys from your wallet signature and writes them to .polymarket-api-creds. Run once before npm start if you want to pre-generate credentials. The bot also auto-generates them on first start in EOA mode.

Validate credentials:

npm run test-api-creds

Common Patterns

Conservative testing setup

POSITION_MULTIPLIER=0.05
MAX_TRADE_SIZE=5
MIN_TRADE_SIZE=1
MAX_SESSION_NOTIONAL=20
ORDER_TYPE=FOK
USE_WEBSOCKET=false

WebSocket-only market channel (lower latency)

USE_WEBSOCKET=true
USE_USER_CHANNEL=false
WS_ASSET_IDS=0xTokenId1,0xTokenId2

LIMIT orders with slippage buffer

ORDER_TYPE=LIMIT
SLIPPAGE_TOLERANCE=0.03

Troubleshooting

Bot starts but no trades detected

Verify TARGET_WALLET is a valid Polymarket wallet with recent activity
Check POLL_INTERVAL — default 2000ms; lower means more API calls
Confirm the target wallet trades on Polymarket (not just holds positions)

ethers version conflicts

The project pins ethers v5. Do not upgrade to v6 — the CLOB SDK requires v5
Run npm ls ethers to check for duplicate versions

Approval transactions failing

Ensure the wallet has sufficient POL (MATIC) for gas on Polygon mainnet
Try increasing MIN_PRIORITY_FEE_GWEI and MIN_MAX_FEE_GWEI if transactions stall

generate-api-creds fails

Confirm WALLET_PRIVATE_KEY is correct and 0x-prefixed
For SIG_TYPE=1/2, ensure PROXY_WALLET_ADDRESS matches your Polymarket account

Orders rejected by CLOB

FOK orders fail if insufficient liquidity — try ORDER_TYPE=FAK or LIMIT
Check SLIPPAGE_TOLERANCE isn't too tight for illiquid markets

Session notional cap hit immediately

MAX_SESSION_NOTIONAL resets per process run; restart the bot to reset
Set MAX_SESSION_NOTIONAL=0 to disable the cap entirely

Wallet Requirements

USDC.e on Polygon mainnet (collateral for trades)
POL (formerly MATIC) for gas fees
Approve USDC.e for Polymarket CTF Exchange and CLOB contracts (bot does this automatically on first EOA run)